Incorrect call set_exit_wait_early_message
Incorrect call set_exit_wait_early_message

obmc_boot_test.py function stop_boot_test was incorrectly calling
set_wait_early_exit_message.  The correct name is set_exit_wait_early_message.

Change-Id: Ie1ce60f3e32261af43b3ccf274251f27198996b0
Signed-off-by: Michael Walsh <10404802c7de463f402c4a18638106ca1b12ef61@us.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation